package com.company;

import java.util.Scanner;

/**
 * @author jrue
 * @version 1.0
 * @date 2020/3/24 18:54
 */
public class Main72 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();

        if (m == 0 && n != 0) {
            System.out.printf("%.4f",1.0000);
            return;
        }
        double res = 0;
        double b = 1;
        for (int i = 0; i < m; i++) {
            res = b * ( (double) n /( m - i + n)) + res;
            b = ((double) (m - i) / (m + n - i)) * ((double) (m - i - 1) / (m + n - 1 - i));
            i++;
        }

        System.out.printf("%.4f",res);
    }

}
